Optical disk having tracking polarity information, and apparatuses and methods for recording and reproducing user data on the same

ABSTRACT

An optical disc includes tracking polarity information. The optical disc includes a clamping area, a lead-in area, a data area, and a burst cutting area (BCA). The BCA is present between the clamping area and the lead-in area and in which information regarding the optical disc is recorded, and the information is read before performing tracking in the data area. Accordingly, it is possible to obtain the tracking polarity information and/or reflectivity information without trial and error and directly record or reproduce user data in a data area of the optical disc.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/695,393, filed Oct. 29, 2003, which claims the priority of KoreanPatent Application No. 2002-67968 filed Nov. 4, 2002, in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical disc, and more particularly,to an optical disc having at least one recording layer, and apparatusesand methods for recording and reproducing data on the same.

2. Description of the Related Art

Compact discs (CDs) and digital versatile discs (DVDs) are the mostpopular types of data storage media. In general, user data is recordedon pits of a recording layer of a read-only optical disc and recorded bychanging a phase of a phase change material (PCM) on the recording layerof a rewritable optical disc which is covered with the PCM.

A pickup, which is included in an optical disc reproducing apparatus,detects a precise position of a track in which the user data isrecorded, receives a laser beam reflected from the track, and reads theuser data from the laser beam. A signal that the pickup uses to detect aposition of a desired track is called a tracking signal. The trackingsignal is obtained when a photo diode, which has a plurality of lightreceiving parts, receives the laser beam. Signals are generated fromlights received by the respective light receiving parts, and then, thesignals are added together or subtracted from each other. The trackingsignal curves like an S-shape and right and left sides of the trackingsignal, which are divided with respect to a central point of thetracking signal, have opposite polarities.

The polarities of the tracking signal change according to a type of theoptical disc or physical characteristics of the recording layer on theoptical disc, such as the physical characteristics of the pit or thetrack. In other words, the polarities of the tracking signal change from(−) to (+) and from (+) to (−) according to the type of optical disc orthe physical characteristics of the recording layer. Therefore, when theoptical disc is loaded into a conventional optical disc reproducingapparatus, the apparatus determines the polarity of a tracking signal bytrial and error, detects the position of the track in which the userdata is recorded based on the polarity, and reads the user data from thetrack. That is, the conventional optical disc reproducing apparatusspends considerable time in detecting the polarity of the trackingsignal before reading the user data, thereby delaying a reproduction ofthe user data.

Meanwhile, a reflectivity of the optical disc is a ratio of a power ofthe laser beam reflected from the recording layer of the optical disc tothe power of the laser beam incident on the recording layer. Thereflectivity also depends on the type of optical disc or the physicalcharacteristics of the recording layer, and therefore, the conventionaloptical disc reproducing apparatus detects the reflectivity by trial anderror.

SUMMARY OF THE INVENTION

The present invention provides an optical disc from which informationregarding a polarity of a tracking signal and/or a reflectivity iseasily recognized, and apparatuses and methods for recording andreproducing information on the same.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

According to an aspect of the present invention, there is provided anoptical disc including a clamping area; a lead-in area; a data area; anda burst cutting area (BCA) which is present between the clamping areaand the lead-in area and in which information regarding the optical discis recorded, wherein the information is read before performing trackingin the data area.

According to an aspect of the present invention, the informationregarding the optical disc is at least one of tracking polarityinformation and reflectivity information, and the tracking polarityinformation and the reflectivity information are recorded with a patternof crystalline or non-crystalline marks.

According to an aspect of the present invention, the recording of thetracking polarity information begins at leading bytes in the BCA and isrepeatedly recorded.

According to an aspect of the present invention, first two bits of theleading bytes of the tracking polarity information include identifiersof the respective tracking polarity information that is repeatedlyrecorded several times, and other six bits include remaining informationof the tracking polarity information.

According to an aspect of the present invention, one of the six bitsincludes flag information that indicates whether other information isrecorded in the BCA, and the other five bits of the six bits include thetracking polarity information that indicates a polarity of a trackingsignal related to each recording layer of the optical disc.

According to another aspect of the present invention, there is providedan optical disc including a first recording layer in which a firstlead-in area, a first data area, and a first lead-out area are formed;and a second recording layer in which a second lead-in area, a seconddata area, and a second lead-out area are formed, wherein at least oneof the first and second recording layers includes a burst cutting area(BCA), in which information regarding the optical disc is recorded, andthe information is read before performing tracking in the first andsecond data areas.

According to an aspect of the present invention, the informationregarding the optical disc is at least one of tracking polarityinformation and reflectivity information, and the tracking polarityinformation and the reflectivity information are recorded with a patternof crystalline or non-crystalline marks.

According to an aspect of the present invention, the recording of thetracking polarity information begins in leading bytes in the BCA and isrepeatedly recorded.

According to yet another aspect of the present invention, there isprovided a method of recording information on an optical disc that hasat least one recording layer, the method including recording at leastone of tracking polarity information and reflectivity information in aburst cutting area (BCA) of the recording layer.

According to still another aspect of the present invention, there isprovided a method of reproducing information on an optical disc whichhas at least one recording layer, the method including reading trackingpolarity information in a burst cutting area (BCA) of the recordinglayer, and analyzing the read tracking polarity information, outputtingan analysis result indicative thereof, performing tracking in therecording layer of the optical disc using the analysis result, andrecording or reproducing user data on the optical disc.

According to still another aspect of the present invention, there isprovided a method of reproducing information on an optical disc whichhas at least one recording layer, the method including readingreflectivity information in a burst cutting area (BCA) of the recordinglayer; and analyzing the reflectivity information and outputting ananalysis result indicative thereof, adjusting the write or read power ofa laser beam using the analysis result, and recording or reproducinguser data on the optical disc.

According to still another aspect of the present invention, there isprovided an optical disc recording apparatus including a controllercreating at least one of tracking polarity information and reflectivityinformation; and a recording unit recording the at least one of trackinginformation and reflectivity information created by the controller in aa burst cutting area (BCA) of an optical disc.

According to still another aspect of the present invention, there isprovided an optical disc reproducing apparatus including a reading unitreading at least one of tracking polarity information and reflectivityinformation from a burst cutting area (BCA) of an optical disc, and acontroller analyzing the information read by the reading unit andoutputting an analysis result indicative thereof, and recording orreproducing user data on the optical disc using the analysis result.

According to an aspect of the present invention, there is provided anoptical disc, comprising: a first recording layer formed on the opticaldisc; a second recording layer formed on the optical disc, wherein thefirst recording layer and a second recording layer each comprise aclamping area, a burst cutting area (BCA), a lead-in area, and alead-out area, wherein the clamping area is an area that is pressurizedto clamp the optical disc, and the BCA is an area in which trackingpolarity information and/or reflectivity information is recorded; and adata area recording user data between the lead-in area and the lead-outarea.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/other other aspects and advantages of the presentinvention will become more apparent by describing in detail aspectsthereof with reference to the attached drawings in which:

FIG. 1 is a schematic block diagram of an optical disc recordingapparatus, according to an aspect of the present invention;

FIG. 2 is a schematic block diagram of an optical disc reproducingapparatus, according to an aspect of the present invention;

FIG. 3 is a schematic block diagram of an optical disc, according to anaspect of the present invention;

FIGS. 4A and 4B are schematic block diagrams of the optical disc,according to another aspect of the present invention;

FIGS. 5A and 5B are schematic block diagrams of the optical discaccording to still another aspect of the present invention;

FIG. 6A illustrates a data structure of a burst cutting area (BCA) ofthe optical disc, according to an aspect of the present invention;

FIG. 6B illustrates the data structure of the BCA of the optical disc,according to another aspect of the present invention;

FIG. 7 illustrates the data structure of information recorded on the BCAof the optical disc, according to an aspect of the present invention;

FIG. 8 is a flowchart illustrating a method of reproducing data from theoptical disc, according to an aspect of the present invention; and

FIG. 9 is a flowchart illustrating the method of reproducing data fromthe optical disc, according to another aspect of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present aspects of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The aspects are described below in order to explain thepresent invention by referring to the figures.

FIG. 1 is a schematic block diagram of an optical disc recordingapparatus, according to an aspect of the present invention. Referring toFIG. 1, the recording apparatus includes a recording unit 1 and acontroller 2 to record information regarding a polarity of a trackingsignal and/or a reflectivity of an optical disc 100 on a burst cuttingarea (BCA) on the optical disc 100. The controller 2 creates theinformation regarding the polarity of the tracking signal and/or thereflectivity of the BCA and the recording unit 1 records at least one oftracking polarity information and reflectivity information on the BCA.Thus, the BCA of the optical disc 100, according to an aspect of thepresent invention, includes the tracking polarity information and/or thereflectivity information.

FIG. 2 is a schematic block diagram of an optical disc reproducingapparatus, according to an aspect of the present invention. Referring toFIG. 2, the reproducing apparatus includes a reading unit 4 and acontroller 5. The reading unit 4 reads the tracking polarity informationand/or the reflectivity information from the BCA on the optical disc100, according to an aspect of the present invention, and provides ananalysis result indicative thereof to the controller 5. Then, thecontroller 5 analyzes the tracking polarity information and/or thereflectivity information and reproduces user data from the optical disc100 based on the analysis result.

The recording apparatus of FIG. 1 is an apparatus used in a masteringprocess by a disc manufacturer. The reproducing apparatus of FIG. 2 isan apparatus to reproduce the tracking polarity information and/or thereflectivity information, not the user data, from the BCA. Thus, thereproducing apparatus of FIG. 2 can be included in both the optical discrecording apparatus and the optical disc reproducing apparatus becausethe reproduction of the above information can be carried out whenrecording or reproducing the user data on the optical disc 100.

FIG. 3 is a schematic block diagram of the optical disc 100, accordingto an aspect of the present invention. Referring to FIG. 3, a firstrecording layer l0 is formed on the optical disc 100. The firstrecording layer l0 includes a clamping area C, the BCA B, a lead-in areaLI, and a lead-out area LO. The clamping area C is an area that ispressurized by a clamping tool in order to clamp the optical disc 100.In general, the clamping area C is circular band shaped and formed in aninner portion of the optical disc 100. The BCA B is an area in which thetracking polarity information and/or the reflectivity information isrecorded. The particulars of the optical disc 100, such as acorresponding serial number and manufacturing date, may be furtherrecorded in the BCA B. A data area in which the user data is recorded,is present between the lead-in area LI and the lead-out area LO. If thefirst recording layer l0 is formed of a phase change material (PCM), thetracking polarity information and/or the reflectivity information may berecorded with a pattern of crystalline and/or non-crystalline marks. Amethod of recording information in the BCA B is disclosed in KoreanPatent Application No. 2001-47957 entitled “Optical Disc and Methods forRecording and Reproducing Essential Information of Optical Disc,” alsofiled by the present applicant.

FIGS. 4A and 4B are schematic block diagrams of the optical disc 100,according to another aspect of the present invention. Referring to FIGS.4A and 4B the first recording layer l0 and a second recording layer l1are formed on the optical disc 100. Each of the first recording layer l0and the second recording layer l1 includes the clamping area C, thelead-in area LI, and the lead-out area LO. The data area in which theuser data is recorded is present between the lead-in area LI and thelead-out area LO. The clamping area C, the lead-in area LI, and thelead-out area LO are the same as those explained with respect to FIG. 3,and therefore, their descriptions will not be repeated here. Further,the BCA B is present between the clamping area C and the lead-in area LIof the first recording layer l1. The tracking polarity informationand/or the reflectivity information is recorded in the BCA B, accordingto an aspect of the present invention. The particulars of the opticaldisc 100, such as the corresponding serial number and the manufacturingdate, may be further recorded in the BCA B. If the first recording layerl0 is formed of the phase change material (PCM), the tracking polarityinformation and/or the reflectivity information may be recorded with thepattern of the crystalline and/or the non-crystalline marks.

FIGS. 5A and 5B are schematic block diagrams of the optical disc 100,according to still another aspect of the present invention. Referring toFIGS. 5A and 5B, the first recording layer l0 and the second recordinglayer l1 are formed on the optical disc 100. Each of the first recordinglayer 10 and the second recording layer l1 includes a clamping area C, alead-in area LI, and a lead-out area LO. The data area in which the userdata is recorded is present between the lead-in area LI and the lead-outarea LO. The clamping area C, the lead-in area LI, and the lead-out areaLO are the same as those explained with respect to FIG. 3, andtherefore, their descriptions will not be repeated here. According to anaspect of the present invention, the BCA B is formed on the secondrecording layer l1, unlike in FIGS. 4A and 4B in which the BCA B ispresent on the first recording layer l0. That is, the BCA B of FIGS. 5Aand 5B is present between the clamping area C and the lead-in area LI ofthe second recording layer l1. If the second recording layer l1 isformed of the phase change material (PCM), the tracking polarityinformation or reflectivity information may be recorded with a patternof crystalline and/or non-crystalline marks.

In conclusion, the optical disc 100 of FIGS. 5A and 5B is different fromthat of FIGS. 4A and 4B in that the BCA B is present in the secondrecording layer, not the first recording layer.

FIG. 6A illustrates a data structure of the BCA of the optical disc 100,according to an aspect of the present invention. Referring to FIG. 6A,the tracking polarity information is recorded in the BCA, according toan aspect of the present invention. The tracking polarity informationprovides the polarity of the tracking signal related to the optical disc100. The tracking signal curves like an S-shape and corresponding rightand left sides, which are divided with respect to the central point ofthe tracking signal, have opposite polarities. The polarity of thetracking signal changes according to a type of the optical disc 100, orphysical characteristics of the recording layer such as the physicalcharacteristics of a pit or a track. In other words, the polarities ofthe tracking signal change from (−) to (+) and (+) to (−) according tothe type of the optical disc 100 or the physical characteristics of therecording layer. The particulars of the optical disc 100 may be furtherrecorded in the BCA, as well as the tracking polarity information.

FIG. 6B illustrates a data structure of the BCA of the optical disc 100,according to another aspect of the present invention. The trackingpolarity information and/or the reflectivity information is recorded inthe BCA, according to an aspect the present invention. Here, thetracking polarity information is as described with reference to FIG. 6A.The reflectivity information provides the reflectivity of the opticaldisc 100, which is a ratio of the power of a laser beam reflected fromthe recording layer of the optical disc 100 to the power of the laserbeam incident on the recording layer. The reflectivity also changesaccording to the type of the optical disc 100 or the physicalcharacteristics of the recording layer.

Meanwhile, the tracking polarity information is recorded in both theBCAs of FIGS. 6A and 6B, but only the reflectivity information can berecorded if needed.

FIG. 7 illustrates a data structure of the information recorded in theBCA of the optical disc 100, according to an aspect of the presentinvention. In detail, FIG. 7 shows an example of the BCA in the opticaldisc 100 having two recording layers as shown in FIGS. 4 and 5. Thetracking polarity information is repeatedly recorded four times in theBCA and the recording begins at leading bytes of the BCA. First two bitsb1b0 of the tracking polarity information are identifiers of therespective information that is repeatedly recorded. If the first twobits b1b0 are 00, the information indicates that first tracking polarityinformation is recorded in the BCA. If the first two bits b1b0 are 01,the information indicates that second tracking polarity information isrecorded in the BCA. If the first two bits b1b0 are 10, the informationindicates that third tracking polarity information is recorded in theBCA. If the first two bits b1b0 are 11, the information indicates thatfourth tracking polarity information is recorded in the BCA. Repetitiverecording of the information increases a robustness of the information.Even if an error occurs in one of the repeated recordings, it ispossible to read desired information from the other recordings. Theother six bits b7b6b5b4b3b2 provide the information. The bit b2 includesflag information indicating whether or not other information, i.e., theparticulars of the optical disc 100, is recorded in the BCM. If the bitb2 is 0, the information indicates that the other information is notrecorded in the BCM. If the bit b2 is 1, the information indicates thatthe other information is recorded in the BCM. The bits b7b6b5b4b3represent the tracking polarity information and can be defined asfollows:

-   -   00000: first recording layer=type A, second recording layer=type        B    -   00001: first recording layer=type B, second recording layer=type        A    -   00010: first recording layer=second recording layer=type A    -   00011: first recording layer=second recording layer=type B

For instance, when the other information is not recorded in the BCA, andthe polarities of the tracking signals related to the first and secondrecording layers are type B and type A, respectively, the six bitsb7b6b5b4b3b2 is expressed as ‘000010’. When the other information, suchas the particulars of the optical disc 100, is recorded in the BCA andboth polarities of the tracking signals related to the first and secondrecording layers are type A, the six bits b7b6b5b4b3b2 is expressed as‘000101’.

If 1 byte is not enough to express the tracking polarity information,for example, if the number of recording layers is more than 2, it ispossible to express the tracking polarity information using additionalbits in addition to the 1 byte.

When the optical disc 100 is loaded into a disc drive of the opticaldisc reproducing apparatus, the disc drive easily accesses leading bytesof the BCA so as to read the tracking polarity information and/or thereflectivity information. Accordingly, the recording of the trackingpolarity information and/or reflectivity information may begin on theleading bytes of the BCA.

A method of reproducing the data from the optical disc 100, according toan aspect of the present invention, will now be described. As mentionedabove, the data that is reproduced using the method is not the userdata, but the tracking polarity information and/or the reflectivityinformation recorded in a BCA of the optical disc 100. The reproductionof such data can be performed both when recording and reproducing theuser data in a data area.

FIG. 8 is a flowchart illustrating the method of reproducing the datafrom the optical disc 100, according to an aspect of the presentinvention. Referring to FIG. 8, at operation 801, when the optical disc100 is loaded into the disc drive of the reproducing apparatus of FIG.2, at operation 802 the optical pickup included in the disc drive readsthe tracking polarity information from the BCA of the optical disc 100.At operation 803, the reproducing apparatus (or the disc drive) performsthe tracking on the optical disc 100 using the read tracking polarityinformation without trial and error, and records or reproduces the userdata in a data area of the optical disc 100. In other words, the opticalpickup provides the tracking polarity information to the disc drive, andthen, the disc drive controls the optical pickup using the informationto perform the recording or the reproducing of the user data on theoptical disc 100.

FIG. 9 is a flowchart illustrating the method of reproducing the datafrom the optical disc 100, according to another aspect of the presentinvention. Referring FIG. 9, at operation 901, when the optical disc 100is loaded into the disc drive of the reproducing apparatus of FIG. 2, atoperation 902, the optical pickup included in the disc drive readsreflectivity information from the BCA of the optical disc 100. Atoperation 903, the reproducing apparatus (or the disc drive) adjusts thewrite/read power of the laser beam using the read reflectivityinformation without trial and error, and records or reproduces the userdata in the data area of the optical disc 100. In other words, theoptical pickup provides the reflectivity information to the disc drive,and then, the disc drive controls the optical pickup using theinformation to perform the recording or the reproducing of the user dataon the optical disc 100.

As described above, tracking polarity information and/or reflectivityinformation is recorded in a BCA of an optical disc according to anaspect of the present invention. Accordingly, it is possible to obtainthe tracking polarity information and/or reflectivity informationwithout trial and error and directly record or reproduce user data in adata area of the optical disc.

Although a few aspects of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this aspect without departing from the principlesand spirit of the invention, the scope of which is defined in the claimsand their equivalents.

1. An apparatus for processing data recorded in an information storagemedium comprising a first recording layer and a second recording layer,one of the recording layers comprising a burst cutting area between aclamping area and a lead-in area, and a data area between the lead-inarea and a lead-out area, the apparatus comprising: an optical pickuparranged to emit light to the information storage medium to transferdata with respect to the information storage medium; and a controllerarranged to control the optical pickup to reproduce informationregarding the information storage medium from the burst cutting area inone of the first recording layer and the second recording layer beforetracking the data area, wherein the information regarding theinformation storage medium comprises tracking polarity information foreach of the first and second recording layers.
 2. An information storagemedium comprising a first recording layer and a second recording layer,one of the recording layers comprising a burst cutting area between aclamping area and a lead-in area, and a data area between the lead-inarea and a lead-out area, wherein, the burst cutting area, which isarranged in one of the first recording layer and the second recordinglayer, comprises information regarding the information storage medium,the information regarding the information storage medium comprisestracking polarity information for each of the first and second recordinglayers, and the tracking polarity information is reproduced beforetracking the data area.